1. Field of the Invention
This invention relates to an angle detection sensor.
2. Discussion of Background
A conventional rotation angle sensor is disclosed in Japanese Unexamined Patent Publication No. 110215/1989. This rotation angle sensor is composed of a magnetoresistive element in which a bias magnet is laminated on a magnetic pattern resistance layer of a thin film ferromagnetic material, and a pair of permanent magnets are fixed to a rotation shaft which is disposed for rotation about a center of, and which is orthogonal to an upper surface of the magnetoresistive element. The magnets surround the magnetoresistive element by about equal distances, and poles having different polarities are positioned to face each other. The rotation angle of the permanent magnets is detected as a linear electric signal change.
However, in the above rotation angle sensor, magnetic properties are affected in accordance with the set position of the permanent magnet. Furthermore, the set position is often difficult to adjust properly.